Double whole note

In medieval mensural notation, the brevis was one of the shortest note lengths in use (Gehrkens 1914)—hence its name, which is the Latin etymon of "brief". In "perfect" rhythmic mode, the brevis was a third of a longa, or in "imperfect" mode, half a longa (Hoppin 1978, ).

In modern notation, a breve is commonly represented in either of two ways: by a hollow oval note head, like a whole note, with one or two vertical lines on either side, as on the left of the image, or as the rectangular shape also found in older notation, shown in the middle of the image (Jacob 1960, 21; Read 1969, 459).

Because it lasts longer than a bar in most modern time signatures in common use, the breve is rarely encountered except in English music, where the half-note is often used as the beat unit (Gehrkens 1914, 11).

Breve rest

A related symbol is the double whole rest (double rest or breve rest), which usually denotes a silence for the same duration (Burrowes 1874, 41; Read 1969, 93). Double whole rests are drawn as filled-in rectangles occupying the whole vertical space between the second and third lines from the top of the musical staff. They are often used in long silent passages which are not divided into separate bars to indicate a rest of two bars (Read 1969, 101). This and longer rests are collectively known as multiple rests (Read 1969, 99).

Alla breve, the time signature ²
₂, takes its name from the note value breve. In the mensural notation of the Renaissance, it was an alternative term for proportio dupla, which meant that the brevis was to be considered the unit of time (tactus), instead of the usual semibrevis. The old symbol , used as an alternative to the numerical proportion 2:1 in mensural notation, is carried over into modern notational practice to indicate a smaller relative value per note shape. It is normally used for music in a relatively quick tempo, where it indicates two minim (half note) beats in a bar of four crotchets (quarter notes), while is the equivalent of ⁴
₄, with four crotchet beats (Wright 2001).

• List of musical symbols

• Baker, Theodore. 1895. “Note”, A Dictionary of Musical Terms: Containing Upwards of 9,000 English, French, German, Italian, Latin, and Greek Words and Phrases, third edition, revised and enlarged. New York: G. Schirmer.
• Burrowes, John Freckleton. 1874. Burrowes' Piano-forte Primer: Containing the Rudiments of Music Adapted for Either Private Tuition Or Teaching in Classes Together with a Guide to Practice, new edition, revised and modernized, with important additions, by L.H. Southard. Boston and New York: Oliver Ditson.
• Gehrkens, Karl Wilson. 1914. Music Notation and Terminology. New York: The A.S. Barnes Co.; Chicago: Laidlaw Brothers.
• Gerou, Tom, and Linda Lusk. 1996. Essential Dictionary of Music Notation. Essential Dictionary Series. Los Angeles: Alfred Music Publishing. ISBN 0-88284-730-9.
• Hoppin, Richard H. 1978. Medieval Music. W W Norton & Company ISBN 0-393-09090-6.
• Jacob, Archibald. 1960. Musical Handwriting: Or, How to Put Music on Paper, A Handbook for All Musicians, Professional and Amateur, second edition, revised. London: Oxford University Press.
• Read, Gardner. 1969. Music Notation: A Manual of Modern Practice, second edition. Boston: Alleyn and Bacon, Inc.
• Wright, Peter. 2001. "Alla breve". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.